Hot standby means that a primary Operations Sentinel server alone monitors the output of managed systems, and if the primary Operations Sentinel server fails, a secondary Operations Sentinel server takes over the monitoring.
Benefits
Hot standby permits your operations staff to continue monitoring and remotely operating a set of managed systems even if a hardware or software failure makes the primary Operations Sentinel server unavailable.
In some environments you can choose either hot standby or concurrent monitoring, depending on your monitoring and control requirements.
In most situations, concurrent monitoring is preferable. However, hot standby may have advantages over concurrent monitoring if any of the following conditions apply:
The volume of information causes network bandwidth to be a concern.
This method sends data to only one server rather than two, so it generates half the traffic.
There are external alert actions that should not be duplicated on both the primary and secondary Operations Sentinel servers.
To avoid duplicating an external alert action with concurrent monitoring, each Operations Sentinel server must have a different active alert policy. However, when the primary Operations Sentinel server fails, the secondary server generally should start using an alert policy like the one on the failed primary, but this requires a manual action to change alert policies. Hot standby avoids this complication.
[UNIX]
You want different SP-AMS commands sent to the managed system from the primary and secondary Operations Sentinel servers.
This case applies if the autoactions should not send commands to the same managed system twice. To avoid duplication with concurrent monitoring of UNIX and Linux systems, each Operations Sentinel server must have a different active SP-AMS database.
When the primary Operations Sentinel server fails, the secondary server should activate using an autoaction database like the one on failed primary server. For this to occur, you must either activate the databases manually or use SP-AMS to activate the new database upon detecting the loss of the primary server. By using hot standby you avoid this complication. This is not a consideration for managed MCP systems because the Operations Sentinel MCP agent can only accept input from one Operations Sentinel server at a time.